1. Field of the Invention
The invention relates to a connector with an inertial locking function.
2. Description of the Related Art
A connector has housings and terminal fittings are mounted in the housings. The housings can be connected to electrically connect the terminal fittings. A resilient contact on one terminal fitting is brought resiliently into contact with the mating terminal fitting to ensure contact reliability between the two terminal fittings. Thus, a frictional resistance is created when the housings are connected due to the resilient contact between the terminal fittings and acts as a connection resistance against the connection of the housings. A connection resistance due to the resilient deformation of a lock arm for locking the housings in their properly connected state also is created in the connecting process. A watertight connector also exhibits a connection resistance due to frictional resistance between a rubber seal ring mounted between the housings. Thus, a large connection resistance is unavoidable in the connecting process and is a sum of the above connection resistances.
Increased connection resistance due to the terminal fittings, the lock arm and the seal ring at an intermediate stage of the connecting operation may be interpreted incorrectly as complete insertion, and an operator may end the connecting operation in response to such increased connection resistance.
An xe2x80x9cinertial locking constructionxe2x80x9d is adopted widely to prevent incomplete connection. This construction has a resistance arm in one housing that abuts the other housing before the connection resistance is created. Thus, a resistance force larger than the connection resistance is created intentionally. An operation force that exceeds the intentional resistance force by the resistance arm must be created. This operation force also is larger than the connection resistance is given. The abutment of the resistance arm is canceled during the connection process. The connecting operation of the housings then proceeds at a stroke by a force given to cancel the intentional resistance. As a result, the two housings reach a properly connected state.
The connecting operation will proceed at a stroke after cancellation of the intentional resistance if there is a large difference between the operation force required to cancel the intentional resistance and a sum of the connection resistances by the terminal fittings, the lock arm, the seal ring after the cancellation of the resistance. The connection resistances may be set smaller and/or the resistance canceling force may be set larger to maximize this difference. However, smaller connection resistances cause a reduction in the contact reliability between the terminal fittings, a reduction in the reliability of a locking function by the lock arm and a reduction in the reliability of a sealing function by the seal ring. On the other hand, a larger resistance canceling force results in an increased burden on the operator. Thus, it has been difficult to improve the reliability of an inertial locking function by enlarging the difference between the resistance canceling force and the connection resistances.
The present invention was developed in view of the above problems and an object thereof is to improve the reliability of an inertial locking function.
The invention relates to a connector with first and second housings that are connectable with each other. Terminal fittings are mounted in the housings and connect with each other in the process of connecting the housings. The connection of the terminal fittings creates a frictional resistance. The first housing has a resistance arm and the second housing has an abutment, which together form an inertial locking means. The resistance arm contacts the abutment during a connecting operation and creates a resistance force. A resistance canceling force that exceeds the resistance force can be given to the housings to deform the resistance arm away from the abutment and to cancel the resistance. The connecting operation of the housings proceeds at a stroke after the cancellation of the resistance.
A tubular seal is mounted on a peripheral surface of one housing and resiliently contacts a peripheral surface of the mating housing in the process of connecting the housings. The seal and the peripheral surface of the mating housing preferably contact in the process of connecting the housings and a connection resistance created by the resilient deformation of the seal reaches a maximum before the resistance arm and the abutment abut.
A maximum value of the connection resistance due to resilient deformation of the seal preferably is less than the resistance canceling force.
The connection resistance caused by the ring reaches a maximum before the resistance of the inertial locking means is created. Thus, the maximum connection resistance created in the process of continuing the connecting operation in a single stroke after the cancellation of the resistance by the inertial locking means is smaller by the magnitude of the connection resistance caused by the seal ring. Therefore, a difference between the operation force required to cancel the resistance of the resistance arm and the connection resistance created after the cancellation of the resistance becomes larger. Accordingly, the connection is more likely to proceed in a single stroke.
The resilient restoring forces of the seal between the peripheral surfaces of the housings concentrically position the housings relative to one another at an early stage of the connecting process. Thus the resistance arm will not displace transversely relative to the abutment, and the reliability of the inertial locking function is assured.
A resilient contact rib is formed near the front end of the seal and assures a sealing engagement with both the housing and the mating housing. This sealing engagement defines a loose-movement preventing means for preventing loose backward movements of the front end of the seal.
The resilient contact near the front of the seal creates a connection resistance before the resistance arm and the abutment engage. However, the loose movement preventing means assures that the frictional resistance between the seal and the mating housing will not push the front end of the seal back. Therefore, even a long seal will not buckle.
The seal is squeezed between an inner peripheral surface of a receptacle of the mating housing and a fittable portion of the housing fit into the receptacle.
These and other features of the invention will become more apparent upon reading of the following detailed description and accompanying drawings. It should be understood that even though embodiments are described separately, single features may be combined to additional embodiments.